Q. The path difference between two waves $y_{1} = a_{1}sin\left( \omega t - \frac{2\pi x}{\lambda} \right)$ and $y_{2} = a_{2}\cos\left( \omega t - \frac{2\pi x}{\lambda} + \phi \right)$is

A) $\frac{\lambda}{2\pi}(\phi)$
B) $\frac{\lambda}{2\pi}\left( \phi + \frac{\pi}{2} \right)$
C) $\frac{2\pi}{\lambda}\left( \phi - \frac{\pi}{2} \right)$
D) $\frac{2\pi}{\lambda}(\phi)$
Explanation

(b) $y_{2} = a_{2}\cos\left( \omega t - \frac{2\pi x}{\lambda} + \phi \right)$
$= a_{2}\sin\left\lbrack \frac{\pi}{2} + \left( \omega t - \frac{2\pi x}{\lambda} + \phi \right) \right\rbrack$
Compare it with $y_{1} = a_{1}sin\left( \omega t - \frac{2\pi x}{\lambda} \right)$
Phase difference$= \left( \frac{\pi}{2} + \phi \right)$
$\therefore\ $Path difference $= \frac{\lambda}{2\pi}\left( \frac{\pi}{2} + \phi \right)$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

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